The present invention relates to apparatus for transferring blood into a tube, and more particularly to an apparatus which can be utilized to ascertain the velocity of descent of red blood cells in a tube which is provided with a graduated scale.
Apparatus of the type to which the present invention pertains is disclosed, for example, in Swiss Pat. No. 417,158. As a rule, a supply of blood is introduced into a vessel from which the blood is transferred into the aforementioned tube. Problems arise in connection with the transfer of accurately metered quantities of blood into the tube because the supply of blood in the vessel is normally covered by a head of foamed blood. One end of the preferably cylindrical vessel is open to allow for insertion of one end portion of the tube whereby the foam penetrates into the tube together with blood and prevents the blood from forming a clearly defined meniscus at a desired level, e.g., in register with the zero graduation of a scale on the tube. One end portion of the tube is introduced into the vessel not unlike a piston into a cylinder whereby the head of foam invariably enters the tube and obscures the exact locus of the top level of the solid column of blood in the tube.